car cranks but will not start

[evandael]

tl;dr car gets fuel, i think it's ignition related.

'88 325i

- car ran up until this past saturday. died at a redlight. later that day it was running fine. now it cranks but won't start.

since then..

- replaced fuel pump, fpr, and engine bay fuel lines just because
- PO had 'rearranged' the main relay, fuel pump relay, and O2 heater relays. these have been corrected. note; before this, THE CAR DID RUN
- fuel pump runs in run or start, verified with 30-87 jumper anyway. it's good.


the only thing I'm thinking it could be is 2.5 green wire from the ignition switch. or would a messed up DME cause this?


anybody have experience with a similar problem?

[jlevie]

If the fuel pump runs when the engine is cranking, check for spark and check to see if the timing belt has failed (the cam should turn when cranking).

[jhaurimn]

If you have a volt meter, rule out crank and camshaft position sensors

[NoM54me]

I had this exact problem for a couple of months, engine would spontaneously shut off, then not restart for 10 minutes to three hours. Eventually, it stopped at my work and wouldn't restart after 9 hours. Turned out to be the OBC relay by hood release. I cut the solid green wire and green wire with a red stripe, connected them to bypass the OBC, and it started right up. The OBC "code" function had gone screwy. This takes 30 seconds, and if it's bad, you won't get a spark. It's part of the ignition switch circuit. The problem is that it's usually intermittent, which is really problematic for diagnostics. I seldom see this posted as a fix for similar no-start situations, where every part checks out ok and the engine still will not start.

[storm-e]

I bypassed the obc relay. And my car started right up. Thanks for the advice. It's such a fucking relief to finally figure out what the problem was.